1. Field of the Invention
The present invention relates to a method and an apparatus for feeding workpieces, such as long round bars or pipes, to an arbitrary cutting machine, such as a band saw machine or a disc cutter, and more particularly to a feeding method and a feeding apparatus for a workpiece conveying and feeding apparatus for conveying and feeding a workpiece to a cutting machine such that the workpiece can accurately be located to a predetermined position in a workpiece conveying and feeding passage.
2. Description of the Related Art
Hitherto, a method has been employed in which a workpiece conveying and feeding unit for conveying a workpiece, such as a long round rod or a pipe, in the lengthwise direction to convey the workpiece to an arbitrary cutting machine, such as a band saw machine or disc cutter. The unit is disposed in the rear of the cutting machine. A workpiece conveying unit for conveying the workpiece in a direction perpendicular to the lengthwise direction of the workpiece to convey the workpiece to a workpiece conveying passage of the workpiece conveying and feeding unit is provided. Either of the workpiece conveying and feeding unit or the workpiece conveying unit is made to be capable of vertically moving. A plurality of workpieces placed on a plurality of conveying chains provided for the workpiece conveying unit are sequentially conveyed to the workpiece conveying passage of the workpiece conveying and feeding unit. The workpieces conveyed to the workpiece conveying passage are sequentially conveyed to the cutting machine.
More specifically, a structure disclosed in, for example, U.S. Pat. No. 5,086,678 is formed such that a conveyance passage of a workpiece conveying and feeding unit has a plurality of rotative cylindrical rollers. The outer shape of the roller is formed into straight in the lengthwise direction. A workpiece conveying unit for conveying a workpiece W onto the roller has a structure having a plurality of endless conveying chains, in the lengthwise direction of the workpiece conveying passage, extending in a direction of the radius (in the lateral direction) of the workpiece W perpendicular to the lengthwise direction (in the longitudinal direction) of the workpiece conveying passage.
When a plurality of workpieces W placed on the conveying chains are, one by one, placed on the roller, the overall body of the workpiece conveying passage is moved downwards. Then, the workpiece W is conveyed onto the roller which has been moved downwards by driving the conveying chain. Therefore, the workpiece W is brought into contact with a standing roller which is retractable with respect to the upper portion of the conveying chain so as to be located. Then, the overall body of the workpiece conveying passage is moved upwards so that the roller supports the workpiece W.
Since the foregoing conventional structure sometimes encounters a fact that a plurality of workpieces W are conveyed onto the roller if the plurality of the workpieces W having different diameters are placed on the conveying chain and then conveyed onto the roller, the position of the overall body of the workpiece conveying passage can be adjusted in the lateral direction to correspond to the diameter of the workpiece W. Therefore, there arise a problem in that the structure cannot be simplified. Since the structure is employed in which the workpiece W is brought into contact with the standing roller so as to be located, difference in the diameter of the workpieces W results in the axial position of the workpiece W being deviated in the lateral direction. For example, a structure of the cutting machine formed such that a disc cutter, such as a disc saw or a disc cutter, is provided to be capable of vertically moving sometimes encounters deviation of the axial position of the workpiece with respect to the cutting direction of the disc cutter. Therefore, there arises a problem in that the lower end movement position of the cutter must be controlled to be adaptable to the diameter of the workpiece.
Moreover, the above-mentioned conventional structure cannot locate the workpiece W to the connection portion between chain links of the conveying chain when workpieces W having various diameters are placed on the conveying chain. Therefore, there arises a problem in that the space of the apparatus cannot effectively be used.